Aside from the fact that I have an MBA, MCL in Computer Sciences (programming), and about 22 years of experience in the field as a both R&D in tabletop and R&D GM in MMO's, I beg to differ. The simplicity of the 4e rule-set by many has been rightfully touted as basically turning D&D into WoW. The fact that older D&D rules had more rules made the programmers job easier NOT harder. If you have a printed rule you have a clear "if-then". Basic programming 101. I remember when I first entered programming it was BASIC on the C=64 and man was I happy to have a copy of the Rules Cyclopedia sitting next to me. I was even more ecstatic when Players Options came out for 2nd Edition. Made my job SOOO much easier. Once you mentally parse the rules into if-then's, viola, you can code it. With that said I guess I just contradicted myself a bit and should clarify. I guess in the long run it would be easier to code 4th edition because there are less rules, but the difference is so minuscule as to almost render itself moot.
As for the whole branding issue, well, I'm a Kopimist so the whole capitalist drive behind it is junk as far as I'm concerned and largely what will lead to the death of the franchise in the short term. Who wants to keep reworking the code to stick to the flavor of the "current" edition. I sure the hell wouldn't. I'd jut drop it like a rock and recommend people go out and buy an older, tested system, some dice and forget CPRG'ing. Play by yourself if you have to.